The need for improvements in lead-acid storage batteries is widely recognized. Hundreds of articles, patents and research projects have been directed toward improving such batteries. Some of the important characteristics that still need improvement are the cost of the grids (plates), pollution problems associated with the use of lead grids, battery power compared to size and weight, cold starting, mechanical ruggedness, quick charging, long life and multiple cycles (charge-discharge).
One example of a use in which a better battery may be important is in “plug-in hybrid” vehicles. A hybrid car such as a Prius (Toyota) may obtain up to 50 miles per gallon using the combination of a gas and electric motors. In a plug-in hybrid (PHEV—plug hybrid electric vehicles), a large battery is added to a hybrid car so that for the first 20 to 60 miles of driving each day the car becomes, in effect, a purely electric car. However, to be widely accepted, the battery pack for the PHEV should cost less than $3000, about one third the cost of a Li-Ion battery pack.
If a plug-in hybrid, using the batteries of the present invention, could drive 40 miles daily only on its battery, on average, its gas engine would not be used in daily driving. Such a typical car would not use any gasoline.
The plug-in hybrid may be recharged at low cost which may be reflected in electric billing. There is a great interest in such plug-in hybrid cars as they reduce air pollution, especially carbon dioxide, and reduce the need for petroleum imports, see Cal Cars.org and hybrid cars.com.
Professor Andrew Frank of the University of California Davis and his hybrid center have built about 16 plug-in hybrid cars and studied about 40 battery types in a Prius and hybrid SUV. The best batteries were lithium ion types which by themselves could propel the Prius about 60 miles. However a pack of the best batteries for each car would cost over $10,000. In contrast, the conventional lead acid batteries for the same car would cost under $1000. That price is much less than the lithium ion type of batteries. However conventional lead acid batteries propelled the Prius only 20 miles.
It has been suggested that the power of lead acid batteries may be increased by substituting lead plates with other materials. However, it is believed that almost all commercially available lead acid batteries use solid lead plates. There are now a number of projects that have been reported to use non-metal battery plates. Firefly Energy has announced it is developing carbon foam plates, see U.S. Pat. Nos. 979,513 and 7,033,703. Also, Jung et al have filed patent applications on carbon battery plates, see U.S. application Ser. Nos. 11/048,104 and 11/279,103.
One suggestion is to use lead plating on a core of another metal, such as aluminum, copper, steel or titanium. Some of the prior patents and articles about lead-plated cores, or otherwise relevant, are set forth below. All of these patents and articles, and others cited in this patent application, are included herein by reference. Lead is plated on copper in Senoo U.S. Pat. No. 5,223,354; Senoo U.S. Pat. No. 5,093,970; Nann U.S. Pat. No. 4,760,001 and Kiessling U.S. Pat. No. 4,554,228.
U.S. Pat. No. 4,683,648 to Yeh shows a titanium plate covered with lead. U.S. Pat. Nos. 5,379,502, 5,339,873, 5,544,681, and 5,411,821 disclose copper or steel or other materials as cores with titanium and lead layers. U.S. Pat. No. 6,316,148 to Bhardwaj discloses a battery using aluminum foil which is coated with lead. U.S. Pat. Nos. 2,739,997 and 2,713,079 to Carrick disclose aluminum plates electroplated with lead in an aqueous plating bath. U.S. Pat. No. Re: 33133 to Kiessling discloses a copper plate covered with lead.
The following articles may be considered relevant: Dai et al. “Lead-plated titanium grids etc.” 41 Power Sources Conference, Jun. 14-17, 2004; Dai et al. “Corrosion of Lead Plate Titanium etc” (ref. on Google); Kurisawa “Development of Positive Electrodes with Tin Oxide Coating by Applying a Sputtering Technique for Lead Acid Batteries.” Journal Power Sources 1995 (2001) 1-5, 1-9.; Roos et al “Corrosion protection of aluminum surfaces using pyrolytic tin oxide” Appl. Phys. Lett 59(1) July 1991; and Yolshina et al. “A lead-film electrode on an aluminum substrate etc.” Jour. of Power Sources 78, issues 1-2, March 1999, 84-87.